Why the pushrods (still)?

[squala]

It's just that some manufacturers (esp. American) persist in using 60s technology in their cars, and what's the reason for this? Are pushrod/OHV engines really much cheaper to build than more modern OHC or DOHC layouts?

Among the Big 3, only Ford is shying away from this. I think they no longer sell cars with this kind of engine.

[mbt]

what's wrong with pushrods?

pushrods work, and in certain applications, in fact, work very well (as in the corvette). there are certain advantages to pushrods, chief of which is that it allows significantly smaller engine dimensions (mainly reduced height, since there are no overhead cams).

[airshaq20]

It's just that some manufacturers (esp. American) persist in using 60s technology in their cars, and what's the reason for this? Are pushrod/OHV engines really much cheaper to build than more modern OHC or DOHC layouts?

Among the Big 3, only Ford is shying away from this. I think they no longer sell cars with this kind of engine.

You just answered your question - its the cost of building and designing the engine. FYI, it cost HUNDREDS of MILLIONS of $$$ to design, develop and build an engine so we're not just talking hundred of thousands of dollars here.

When you are into any business, you have to think about ROI too.

[mbt]

in the case of GM, i doubt it's because of financial/business reasons. they could well put a Northstar V8 into the corvette, but don't,... hehe. maybe it's a "soul" thing :D

[Karding]

in the case of GM, i doubt it's because of financial/business reasons. they could well put a Northstar V8 into the corvette, but don't,... hehe. maybe it's a "soul" thing :D

GM is so cheap to design a new one. Of course, the longer the engine stays in production, the less money they spend for re-engineering. But for crying out loud, its already a quarter of a century or maybe longer.

And then, the question of supply and demand arises...

[speedy]

Why would you throw away something that may be old school but works! Now, for example the new corvette Z06 has the same pushrod V8 configuration as previous models. But now is bored out to 7.0L ! Producing 500 hp! Its hard to find engines of that size that can produce 500+ hp. (Racing version has 600+) There are so many different ways to increase hp and performance that GM has stayed with a "proven" and "reliable" power plant. Improvements have been made in exhaust and waste management as well as intakes. The other upside to this is the fact that not all corvette fans could afford the latest and newest models. Buying older used models is very appealing because of the price and the accesability of spare parts. (since the technology has been around since the 60's) I think everyone has good points as well, shaq is right about R/D on engines and yes if they are still selling and engine they paid for in the 60's but is still selling like hot cakes, why not! The other thing is the "passion" for the cars that they are in. Corvettes have been known for having a very large following. There are a lot of die hard fans that consistently buy corvette products. I, myself am one of them. I am on my 2nd corvette and I am seriously thinking about the new Z06.

[yebo]

hilig din nila sa hemi engine design and that's why they have push rods. you can't put overhead camshafts on a hemi.

[woodfire]

For me, a HEMI ENGINE is one of the best performing muscle machine ever. Muscle & brawn!!! Old school Hemi Cuda's still can put fear and terror in the street and strip.

Nothing bad about push rods though! Design? Technology? Hey, its all relative. I'll get a push rod Hemi engine or push rod high performance engine anytime.

[yebo]

exactly! why junk something that works very well just because it's a push rod?

[squala]

I'm kinda wondering why Chevy went back to pushrods when they have already built a DOHC layout in the ZR-1. True, they may have spent a lot in research and design for the engine (reflected on the hefty ZR-1 premium over the pushrod model), but shouldn't they have just developed that further for the current car?

[OTEP]

As with mbt's response, pushrods still work better in some applications. Sort of like non-CRDi engines being better than CRDi's in some situations.

Na-explain na ito sa isang technical column sa Car and Driver dati. Hindi ko lang maalala exactly why pushrods are not going to go away anytime soon.

[squala]

True, pushrods work. So do carburetors, fluid shocks, push-button gearboxes, etc., but there's already better technology than those.

I also don't believe BMW will spend so much for research on the M5 and M6 5-liter DOHC engine only to come up with a similar 500 hp output to the Z06's 7-liter pushrod. There are certainly many advantages to all this.

[mazdamazda]

I also don't believe BMW will spend so much for research on the M5 and M6 5-liter DOHC engine only to come up with a similar 500 hp output to the Z06's 7-liter pushrod. There are certainly many advantages to all this.

To note... the Z06 is cheaper by $15K than the M5.

[empy]

To note... the Z06 is cheaper by $15K than the M5.

because they don't bother with the r&d, hehe...they just make a bigger mold for the block

[niky]

I'm kinda wondering why Chevy went back to pushrods when they have already built a DOHC layout in the ZR-1. True, they may have spent a lot in research and design for the engine (reflected on the hefty ZR-1 premium over the pushrod model), but shouldn't they have just developed that further for the current car?

The engine was too big for the new chassis, it was too expensive, and just too well-engineered.

I don't agree completely on the cost of DOHC, though... BMW is a prestige brand... if Honda were making that car, it'd cost maybe $70,000, not over $100,000... but then, their 300hp NSX is about that expensive already.

Americans are very fond of the "don't fix it if it ain't broke" variety of thinking in automotive engineering... hence beam axles, leaf springs, pushrods, ancient HUGE engines producing much less hp/liter than the engines in our japanese compacts... and this is just their sports cars!

Much as I applaud their ability to make old tech last long, there ought to be a limit... I mean, even the Japanese are doing it now... Beam axles are coming back to our cars (*sob*), engines are getting bigger... (2.4-2.5 liters for performance sports compacts? sacrilege!)... Honda's gone almost all-SOHC (better packaging, supposedly)... I won't be surprised if the next Jazz/Fit or Toyota Echo comes with new-age leaf-springs to save even more space... just think about it... they'll call it a "shape-memory alloy flexible horizontal suspension member"...

[squala]

To note... the Z06 is cheaper by $15K than the M5.

That premium goes to refinement, much more creature comforts and overall sophistication. The Z06 is simply a supercar that's made from the cheapest stuff on earth. It's got crude 60s technology with suspension laughed at by the Top Gear guys. The standard Vette produced a fast but messy lap on their track, and I doubt it if the more powerful version is any neater. The M5 should be much more agile.

[mazdamazda]

That premium goes to refinement, much more creature comforts and overall sophistication. The Z06 is simply a supercar that's made from the cheapest stuff on earth. It's got crude 60s technology with suspension laughed at by the Top Gear guys. The standard Vette produced a fast but messy lap on their track, and I doubt it if the more powerful version is any neater. The M5 should be much more agile.

But it still got the job done right?

Chevy Corvette - currently 15th place

BMW M3 CSL - currently 19th place

[empy]

But it still got the job done right?

Chevy Corvette - currently 15th place

BMW M3 CSL - currently 19th place

yep. some people (and it seems like most of them live in america) just want relatively cheap speed. it's why the camaro and mustang have sold so well for so long.

i realize it's unfair to put the corvette in that group, because the vette is an excellent all-around performer, but it's built on the same concept. some people just need to be open-minded that there is more than one way to get high performance

[squala]

The previous-model Mustang's pushrod V8s have been replaced by SOHC (GT) and DOHC (Cobra) units in 1995. The new engines were much more refined, and even if the still pushrod Camaro and its Firebird twin were more powerful, more buyers still got the Mustang. It's a far better everyday car. Those GM duos are simply cheap performance, at the expense of quality, comfort, etc.

At the strip or track, they can get the job done as well, faster than the Mustang, but which pony car is left standing?

[speedy]

That premium goes to refinement, much more creature comforts and overall sophistication. The Z06 is simply a supercar that's made from the cheapest stuff on earth. It's got crude 60s technology with suspension laughed at by the Top Gear guys. The standard Vette produced a fast but messy lap on their track, and I doubt it if the more powerful version is any neater. The M5 should be much more agile.

Yeah but the M5 apparently broke! " A bit fragile " were the words used to describe the M5. Nonetheless, its still a hell of a car!